c7c26a0e64
Reason for revert: Doing a reland where systeminfo.cc includes basictypes.h so that CPU_X86 etc. are defined when they are checked/used. Original issue's description: > Revert of Replace basictypes.h with stdint.h for int_t types. (patchset #1 id:1 of https://codereview.webrtc.org/2604043002/ ) > > Reason for revert: > Very likely cause of Chromium import bot breakage (unused function '__cpuid'), TBD why. > > Original issue's description: > > Replace basictypes.h with stdint.h for int_t types. > > > > Removes basictypes.h for types that only makes use of it for fixed-size-int > > typedefs and replaces it with stdint.h. > > > > BUG=webrtc:6853 > > R=tommi@webrtc.org > > > > Review-Url: https://codereview.webrtc.org/2604043002 > > Cr-Commit-Position: refs/heads/master@{#15867} > > Committed:7fd1a75300> > TBR=tommi@webrtc.org > # Skipping CQ checks because original CL landed less than 1 days ago. > NOPRESUBMIT=true > NOTREECHECKS=true > NOTRY=true > BUG=webrtc:6853 > > Review-Url: https://codereview.webrtc.org/2603203003 > Cr-Commit-Position: refs/heads/master@{#15869} > Committed:7eb0e23bcfBUG=webrtc:6853 TBR=tommi@webrtc.org Review-Url: https://codereview.webrtc.org/2609783002 Cr-Commit-Position: refs/heads/master@{#15873}
75 lines
2.8 KiB
C++
75 lines
2.8 KiB
C++
/*
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* Copyright (c) 2016 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef WEBRTC_BASE_TIMESTAMPALIGNER_H_
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#define WEBRTC_BASE_TIMESTAMPALIGNER_H_
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#include <stdint.h>
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#include "webrtc/base/constructormagic.h"
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namespace rtc {
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// The TimestampAligner class helps translating camera timestamps into
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// the same timescale as is used by rtc::TimeMicros(). Some cameras
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// have built in timestamping which is more accurate than reading the
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// system clock, but using a different epoch and unknown clock drift.
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// Frame timestamps in webrtc should use rtc::TimeMicros (system monotonic
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// time), and this class provides a filter which lets us use the
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// rtc::TimeMicros timescale, and at the same time take advantage of
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// higher accuracy of the camera clock.
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// This class is not thread safe, so all calls to it must be synchronized
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// externally.
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class TimestampAligner {
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public:
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TimestampAligner();
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~TimestampAligner();
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public:
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// Translates camera timestamps to the same timescale as is used by
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// rtc::TimeMicros(). |camera_time_us| is assumed to be accurate, but
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// with an unknown epoch and clock drift. |system_time_us| is
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// time according to rtc::TimeMicros(), preferably read as soon as
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// possible when the frame is captured. It may have poor accuracy
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// due to poor resolution or scheduling delays. Returns the
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// translated timestamp.
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int64_t TranslateTimestamp(int64_t camera_time_us, int64_t system_time_us);
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protected:
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// Update the estimated offset between camera time and system monotonic time.
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int64_t UpdateOffset(int64_t camera_time_us, int64_t system_time_us);
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// Clip timestamp, return value is always
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// <= |system_time_us|, and
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// >= min(|prev_translated_time_us_| + |kMinFrameIntervalUs|,
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// |system_time_us|).
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int64_t ClipTimestamp(int64_t filtered_time_us, int64_t system_time_us);
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private:
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// State for the timestamp translation.
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int frames_seen_;
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// Estimated offset between camera time and system monotonic time.
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int64_t offset_us_;
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// State for the ClipTimestamp method, applied after the filter.
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// A large negative camera clock drift tends to push translated
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// timestamps into the future. |clip_bias_us_| is subtracted from the
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// translated timestamps, to get them back from the future.
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int64_t clip_bias_us_;
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// Used to ensure that translated timestamps are monotonous.
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int64_t prev_translated_time_us_;
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RTC_DISALLOW_COPY_AND_ASSIGN(TimestampAligner);
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};
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} // namespace rtc
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#endif // WEBRTC_BASE_TIMESTAMPALIGNER_H_
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